TY  - JOUR
AU  - Savić, Tatjana D.
AU  - Čomor, Mirjana
AU  - Abazović, Nadica
AU  - Šaponjić, Zoran
AU  - Marinović-Cincović, Milena
AU  - Veljkovic, Dusan Z.
AU  - Zarić, Snežana D.
AU  - Janković, Ivana A.
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/410
AB  - Sensitization of TiO2 crystals and nanoparticles with appropriately chosen organic molecules can lead to a significant shift of their absorption threshold from the UV to the visible, thus improving the absorption of the solar spectrum as well as the efficiency of photocatalytic and photovoltaic devices. Herein, the surface modification of nanocrystalline TiO2 particles (45 angstrom) with salicylate-type ligands consisting of an extended aromatic ring system, specifically 1-hydroxy-2-naphthoic acid and 1,4-dihydroxy-2-naphthoic acid, was found to alter the optical properties of nanoparticles in a similar way to salicylic acid. From both absorption measurements and steady-state quenching measurements of modifier fluorescence upon binding to TiO2 in methanol/ water = 90/10 solutions, stability constants in the order of 10(3) M-1 have been determined at pH 2. Fluorescence lifetime measurements, in the presence and absence of colloidal TiO2 nanoparticles, indicated that the fluorescence quenching process is primarily static quenching, thus proving the formation of a nonfluorescent charge-transfer (CT) complex. The binding structures were investigated by using FTIR spectroscopy. Thermal stability of CT-complexes was investigated by using TPD analysis (TG/DTA/MS). Quantum chemical calculations on model systems using density functional theory (DFT) were performed to obtain the vibrational frequencies of charge transfer complexes, and the calculated values were compared with the experimental data. The investigated ligands have the optimal geometry for binding to surface Ti atoms, resulting in ring coordination complexes of a salicylate type (binuclear bidentate binding-bridging) thus restoring the six-coordinated octahedral geometry of surface Ti atoms. The formation of the inner-sphere CT-complexes results in a red shift of the semiconductor absorption compared to unmodified nanocrystallites and a reduction in the band gap upon the increase in the electron delocalization when including an additional ring. (C) 2015 Elsevier B.V. All rights reserved.
T2  - Journal of Alloys and Compounds
T1  - Anatase nanoparticles surface modified with fused ring salicylate-type ligands (1-hydroxy-2-naphthoic acids): A combined DFT and experimental study
VL  - 630
SP  - 226
EP  - 235
DO  - 10.1016/j.jallcom.2015.01.041
ER  - 

@article{
author = "Savić, Tatjana D. and Čomor, Mirjana and Abazović, Nadica and Šaponjić, Zoran and Marinović-Cincović, Milena and Veljkovic, Dusan Z. and Zarić, Snežana D. and Janković, Ivana A.",
year = "2015",
abstract = "Sensitization of TiO2 crystals and nanoparticles with appropriately chosen organic molecules can lead to a significant shift of their absorption threshold from the UV to the visible, thus improving the absorption of the solar spectrum as well as the efficiency of photocatalytic and photovoltaic devices. Herein, the surface modification of nanocrystalline TiO2 particles (45 angstrom) with salicylate-type ligands consisting of an extended aromatic ring system, specifically 1-hydroxy-2-naphthoic acid and 1,4-dihydroxy-2-naphthoic acid, was found to alter the optical properties of nanoparticles in a similar way to salicylic acid. From both absorption measurements and steady-state quenching measurements of modifier fluorescence upon binding to TiO2 in methanol/ water = 90/10 solutions, stability constants in the order of 10(3) M-1 have been determined at pH 2. Fluorescence lifetime measurements, in the presence and absence of colloidal TiO2 nanoparticles, indicated that the fluorescence quenching process is primarily static quenching, thus proving the formation of a nonfluorescent charge-transfer (CT) complex. The binding structures were investigated by using FTIR spectroscopy. Thermal stability of CT-complexes was investigated by using TPD analysis (TG/DTA/MS). Quantum chemical calculations on model systems using density functional theory (DFT) were performed to obtain the vibrational frequencies of charge transfer complexes, and the calculated values were compared with the experimental data. The investigated ligands have the optimal geometry for binding to surface Ti atoms, resulting in ring coordination complexes of a salicylate type (binuclear bidentate binding-bridging) thus restoring the six-coordinated octahedral geometry of surface Ti atoms. The formation of the inner-sphere CT-complexes results in a red shift of the semiconductor absorption compared to unmodified nanocrystallites and a reduction in the band gap upon the increase in the electron delocalization when including an additional ring. (C) 2015 Elsevier B.V. All rights reserved.",
journal = "Journal of Alloys and Compounds",
title = "Anatase nanoparticles surface modified with fused ring salicylate-type ligands (1-hydroxy-2-naphthoic acids): A combined DFT and experimental study",
volume = "630",
pages = "226-235",
doi = "10.1016/j.jallcom.2015.01.041"
}

Savić, T. D., Čomor, M., Abazović, N., Šaponjić, Z., Marinović-Cincović, M., Veljkovic, D. Z., Zarić, S. D.,& Janković, I. A.. (2015). Anatase nanoparticles surface modified with fused ring salicylate-type ligands (1-hydroxy-2-naphthoic acids): A combined DFT and experimental study. in Journal of Alloys and Compounds, 630, 226-235.
https://doi.org/10.1016/j.jallcom.2015.01.041

Savić TD, Čomor M, Abazović N, Šaponjić Z, Marinović-Cincović M, Veljkovic DZ, Zarić SD, Janković IA. Anatase nanoparticles surface modified with fused ring salicylate-type ligands (1-hydroxy-2-naphthoic acids): A combined DFT and experimental study. in Journal of Alloys and Compounds. 2015;630:226-235.
doi:10.1016/j.jallcom.2015.01.041 .

Savić, Tatjana D., Čomor, Mirjana, Abazović, Nadica, Šaponjić, Zoran, Marinović-Cincović, Milena, Veljkovic, Dusan Z., Zarić, Snežana D., Janković, Ivana A., "Anatase nanoparticles surface modified with fused ring salicylate-type ligands (1-hydroxy-2-naphthoic acids): A combined DFT and experimental study" in Journal of Alloys and Compounds, 630 (2015):226-235,
https://doi.org/10.1016/j.jallcom.2015.01.041 . .

TY  - JOUR
AU  - Savić, Tatjana D.
AU  - Čomor, Mirjana
AU  - Nedeljković, Jovan
AU  - Veljkovic, Dusan Z.
AU  - Zarić, Snežana D.
AU  - Rakić, Vesna M.
AU  - Janković, Ivana A.
PY  - 2014
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/125
AB  - The surface modification of nanocrystalline TiO2 particles (45 angstrom) with catecholate-type ligands having different electron donating/electron withdrawing substituent groups, specifically 3-methylcatechol, 4-methylcatechol, 3-methoxycatechol, 3,4-dihydroxybenzaldehyde and 4-nitrocatechol, was found to alter the optical properties of nanoparticles in a similar way to catechol. The formation of the inner-sphere charge-transfer (CT) complexes results in a red shift of the semiconductor absorption compared to unmodified nanocrystallites and a reduction of the effective band gap, being slightly less pronounced in the case of electron withdrawing substituents. The investigated ligands have the optimal geometry for binding to surface Ti atoms, resulting in ring coordination complexes of the catecholate type (binuclear bidentate binding-bridging) thus restoring six-coordinated octahedral geometry of surface Ti atoms. From the absorption measurements (Benesi-Hildebrand plot), the stability constants in methanol/water = 90/10 solutions at pH 2 in the order of 10(3) M-1 have been determined. The binding structures were investigated by using FTIR spectroscopy. Thermal stability of CT-complexes was investigated by using TG/DSC/MS analysis. Quantum chemical calculations on model systems using density functional theory (DFT) were performed to obtain the vibrational frequencies of charge transfer complexes, and the calculated values were compared with the experimental data.
T2  - Physical Chemistry Chemical Physics
T1  - The effect of substituents on the surface modification of anatase nanoparticles with catecholate-type ligands: a combined DFT and experimental study
VL  - 16
IS  - 38
SP  - 20796
EP  - 20805
DO  - 10.1039/c4cp02197e
ER  - 

@article{
author = "Savić, Tatjana D. and Čomor, Mirjana and Nedeljković, Jovan and Veljkovic, Dusan Z. and Zarić, Snežana D. and Rakić, Vesna M. and Janković, Ivana A.",
year = "2014",
abstract = "The surface modification of nanocrystalline TiO2 particles (45 angstrom) with catecholate-type ligands having different electron donating/electron withdrawing substituent groups, specifically 3-methylcatechol, 4-methylcatechol, 3-methoxycatechol, 3,4-dihydroxybenzaldehyde and 4-nitrocatechol, was found to alter the optical properties of nanoparticles in a similar way to catechol. The formation of the inner-sphere charge-transfer (CT) complexes results in a red shift of the semiconductor absorption compared to unmodified nanocrystallites and a reduction of the effective band gap, being slightly less pronounced in the case of electron withdrawing substituents. The investigated ligands have the optimal geometry for binding to surface Ti atoms, resulting in ring coordination complexes of the catecholate type (binuclear bidentate binding-bridging) thus restoring six-coordinated octahedral geometry of surface Ti atoms. From the absorption measurements (Benesi-Hildebrand plot), the stability constants in methanol/water = 90/10 solutions at pH 2 in the order of 10(3) M-1 have been determined. The binding structures were investigated by using FTIR spectroscopy. Thermal stability of CT-complexes was investigated by using TG/DSC/MS analysis. Quantum chemical calculations on model systems using density functional theory (DFT) were performed to obtain the vibrational frequencies of charge transfer complexes, and the calculated values were compared with the experimental data.",
journal = "Physical Chemistry Chemical Physics",
title = "The effect of substituents on the surface modification of anatase nanoparticles with catecholate-type ligands: a combined DFT and experimental study",
volume = "16",
number = "38",
pages = "20796-20805",
doi = "10.1039/c4cp02197e"
}

Savić, T. D., Čomor, M., Nedeljković, J., Veljkovic, D. Z., Zarić, S. D., Rakić, V. M.,& Janković, I. A.. (2014). The effect of substituents on the surface modification of anatase nanoparticles with catecholate-type ligands: a combined DFT and experimental study. in Physical Chemistry Chemical Physics, 16(38), 20796-20805.
https://doi.org/10.1039/c4cp02197e

Savić TD, Čomor M, Nedeljković J, Veljkovic DZ, Zarić SD, Rakić VM, Janković IA. The effect of substituents on the surface modification of anatase nanoparticles with catecholate-type ligands: a combined DFT and experimental study. in Physical Chemistry Chemical Physics. 2014;16(38):20796-20805.
doi:10.1039/c4cp02197e .

Savić, Tatjana D., Čomor, Mirjana, Nedeljković, Jovan, Veljkovic, Dusan Z., Zarić, Snežana D., Rakić, Vesna M., Janković, Ivana A., "The effect of substituents on the surface modification of anatase nanoparticles with catecholate-type ligands: a combined DFT and experimental study" in Physical Chemistry Chemical Physics, 16, no. 38 (2014):20796-20805,
https://doi.org/10.1039/c4cp02197e . .

TY  - JOUR
AU  - Savić, Tatjana D.
AU  - Šaponjić, Zoran
AU  - Čomor, Mirjana
AU  - Nedeljković, Jovan
AU  - Dramićanin, Miroslav
AU  - Nikolić, Marko G.
AU  - Veljkovic, Dusan Z.
AU  - Zarić, Snežana D.
AU  - Janković, Ivana A.
PY  - 2013
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5601
AB  - The surface modification of nanocrystalline TiO2 particles (45 angstrom) with salicylate-type ligands consisting of an extended aromatic ring system, specifically 3-hydroxy-2-naphthoic acid, 3,5-dihydroxy-2-naphthoic acid and 3,7-dihydroxy-2-naphthoic acid, was found to alter the optical properties of nanoparticles in a similar way to salicylic acid. The formation of the inner-sphere charge-transfer (CT) complexes results in a red shift of the semiconductor absorption compared to unmodified nanocrystallites and a reduction in the band gap upon the increase in the electron delocalization when including an additional ring. The investigated ligands have the optimal geometry for binding to surface Ti atoms, resulting in ring coordination complexes of a salicylate-type (binuclear bidentate binding-bridging) thus restoring the six-coordinated octahedral geometry of surface Ti atoms. From both absorption measurements in methanol/water = 90/10 solutions and steady-state quenching measurements of modifier fluorescence upon binding to TiO2 in aqueous solutions, stability constants in the order of 10(3) M-1 have been determined at pH 2 and pH 3. Fluorescence lifetime measurements, in the presence and absence of colloidal TiO2 nanoparticles, indicated that the fluorescence quenching process is primarily static quenching, thus proving the formation of a nonfluorescent CT complex. The binding structures were investigated by using FTIR spectroscopy. Quantum chemical calculations on model systems using density functional theory (DFT) were performed to obtain the vibrational frequencies of charge transfer complexes, and the calculated values were then compared with the experimental data.
T2  - Nanoscale
T1  - Surface modification of anatase nanoparticles with fused ring salicylate-type ligands (3-hydroxy-2-naphthoic acids): a combined DFT and experimental study of optical properties
VL  - 5
IS  - 16
SP  - 7601
EP  - 7612
DO  - 10.1039/c3nr01277h
ER  - 

@article{
author = "Savić, Tatjana D. and Šaponjić, Zoran and Čomor, Mirjana and Nedeljković, Jovan and Dramićanin, Miroslav and Nikolić, Marko G. and Veljkovic, Dusan Z. and Zarić, Snežana D. and Janković, Ivana A.",
year = "2013",
abstract = "The surface modification of nanocrystalline TiO2 particles (45 angstrom) with salicylate-type ligands consisting of an extended aromatic ring system, specifically 3-hydroxy-2-naphthoic acid, 3,5-dihydroxy-2-naphthoic acid and 3,7-dihydroxy-2-naphthoic acid, was found to alter the optical properties of nanoparticles in a similar way to salicylic acid. The formation of the inner-sphere charge-transfer (CT) complexes results in a red shift of the semiconductor absorption compared to unmodified nanocrystallites and a reduction in the band gap upon the increase in the electron delocalization when including an additional ring. The investigated ligands have the optimal geometry for binding to surface Ti atoms, resulting in ring coordination complexes of a salicylate-type (binuclear bidentate binding-bridging) thus restoring the six-coordinated octahedral geometry of surface Ti atoms. From both absorption measurements in methanol/water = 90/10 solutions and steady-state quenching measurements of modifier fluorescence upon binding to TiO2 in aqueous solutions, stability constants in the order of 10(3) M-1 have been determined at pH 2 and pH 3. Fluorescence lifetime measurements, in the presence and absence of colloidal TiO2 nanoparticles, indicated that the fluorescence quenching process is primarily static quenching, thus proving the formation of a nonfluorescent CT complex. The binding structures were investigated by using FTIR spectroscopy. Quantum chemical calculations on model systems using density functional theory (DFT) were performed to obtain the vibrational frequencies of charge transfer complexes, and the calculated values were then compared with the experimental data.",
journal = "Nanoscale",
title = "Surface modification of anatase nanoparticles with fused ring salicylate-type ligands (3-hydroxy-2-naphthoic acids): a combined DFT and experimental study of optical properties",
volume = "5",
number = "16",
pages = "7601-7612",
doi = "10.1039/c3nr01277h"
}

Savić, T. D., Šaponjić, Z., Čomor, M., Nedeljković, J., Dramićanin, M., Nikolić, M. G., Veljkovic, D. Z., Zarić, S. D.,& Janković, I. A.. (2013). Surface modification of anatase nanoparticles with fused ring salicylate-type ligands (3-hydroxy-2-naphthoic acids): a combined DFT and experimental study of optical properties. in Nanoscale, 5(16), 7601-7612.
https://doi.org/10.1039/c3nr01277h

Savić TD, Šaponjić Z, Čomor M, Nedeljković J, Dramićanin M, Nikolić MG, Veljkovic DZ, Zarić SD, Janković IA. Surface modification of anatase nanoparticles with fused ring salicylate-type ligands (3-hydroxy-2-naphthoic acids): a combined DFT and experimental study of optical properties. in Nanoscale. 2013;5(16):7601-7612.
doi:10.1039/c3nr01277h .

Savić, Tatjana D., Šaponjić, Zoran, Čomor, Mirjana, Nedeljković, Jovan, Dramićanin, Miroslav, Nikolić, Marko G., Veljkovic, Dusan Z., Zarić, Snežana D., Janković, Ivana A., "Surface modification of anatase nanoparticles with fused ring salicylate-type ligands (3-hydroxy-2-naphthoic acids): a combined DFT and experimental study of optical properties" in Nanoscale, 5, no. 16 (2013):7601-7612,
https://doi.org/10.1039/c3nr01277h . .

TY  - JOUR
AU  - Savić, Tatjana D.
AU  - Janković, Ivana A.
AU  - Šaponjić, Zoran
AU  - Čomor, Mirjana
AU  - Veljkovic, Dusan Z.
AU  - Zarić, Snežana D.
AU  - Nedeljković, Jovan
PY  - 2012
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/4698
AB  - Surface modification of nanocrystalline TiO2 particles (45 angstrom) with catecholate-type ligands consisting of an extended aromatic ring system, i.e., 2,3-dihydroxynaphthalene and anthrarobin, was found to alter the optical properties of the nanoparticles in a similar way to modification with catechol. The formation of inner-sphere charge-transfer (CT) complexes results in a red shift of the semiconductor absorption compared to unmodified nanocrystallites and the reduction of the band gap upon the increase of the electron delocalization on the inclusion of additional rings. The binding structures were investigated by FTIR spectroscopy. The investigated ligands have the optimal geometry for binding to surface Ti atoms, resulting in ring coordination complexes of catecholate type (binuclear bidentate binding-bridging) thus restoring the six-coordinated octahedral geometry of surface Ti atoms. From the Benesi-Hildebrand plot, stability constants in methanol/water = 90/10 solutions at pH 2 of the order 10(3) M-1 have been determined. Quantum chemical calculations on model systems using density functional theory (DFT) were performed to obtain vibrational frequencies of charge transfer complexes, and the calculated values were compared with the experimental data.
T2  - Nanoscale
T1  - Surface modification of anatase nanoparticles with fused ring catecholate type ligands: a combined DFT and experimental study of optical properties
VL  - 4
IS  - 5
SP  - 1612
EP  - 1619
DO  - 10.1039/c2nr11501h
ER  - 

@article{
author = "Savić, Tatjana D. and Janković, Ivana A. and Šaponjić, Zoran and Čomor, Mirjana and Veljkovic, Dusan Z. and Zarić, Snežana D. and Nedeljković, Jovan",
year = "2012",
abstract = "Surface modification of nanocrystalline TiO2 particles (45 angstrom) with catecholate-type ligands consisting of an extended aromatic ring system, i.e., 2,3-dihydroxynaphthalene and anthrarobin, was found to alter the optical properties of the nanoparticles in a similar way to modification with catechol. The formation of inner-sphere charge-transfer (CT) complexes results in a red shift of the semiconductor absorption compared to unmodified nanocrystallites and the reduction of the band gap upon the increase of the electron delocalization on the inclusion of additional rings. The binding structures were investigated by FTIR spectroscopy. The investigated ligands have the optimal geometry for binding to surface Ti atoms, resulting in ring coordination complexes of catecholate type (binuclear bidentate binding-bridging) thus restoring the six-coordinated octahedral geometry of surface Ti atoms. From the Benesi-Hildebrand plot, stability constants in methanol/water = 90/10 solutions at pH 2 of the order 10(3) M-1 have been determined. Quantum chemical calculations on model systems using density functional theory (DFT) were performed to obtain vibrational frequencies of charge transfer complexes, and the calculated values were compared with the experimental data.",
journal = "Nanoscale",
title = "Surface modification of anatase nanoparticles with fused ring catecholate type ligands: a combined DFT and experimental study of optical properties",
volume = "4",
number = "5",
pages = "1612-1619",
doi = "10.1039/c2nr11501h"
}

Savić, T. D., Janković, I. A., Šaponjić, Z., Čomor, M., Veljkovic, D. Z., Zarić, S. D.,& Nedeljković, J.. (2012). Surface modification of anatase nanoparticles with fused ring catecholate type ligands: a combined DFT and experimental study of optical properties. in Nanoscale, 4(5), 1612-1619.
https://doi.org/10.1039/c2nr11501h

Savić TD, Janković IA, Šaponjić Z, Čomor M, Veljkovic DZ, Zarić SD, Nedeljković J. Surface modification of anatase nanoparticles with fused ring catecholate type ligands: a combined DFT and experimental study of optical properties. in Nanoscale. 2012;4(5):1612-1619.
doi:10.1039/c2nr11501h .

Savić, Tatjana D., Janković, Ivana A., Šaponjić, Zoran, Čomor, Mirjana, Veljkovic, Dusan Z., Zarić, Snežana D., Nedeljković, Jovan, "Surface modification of anatase nanoparticles with fused ring catecholate type ligands: a combined DFT and experimental study of optical properties" in Nanoscale, 4, no. 5 (2012):1612-1619,
https://doi.org/10.1039/c2nr11501h . .